1. Field of the Invention
The present invention relates to a switch device, such as a mirror switch or a power window switch, which is used in various fields, such as vehicle-mounted apparatuses or various information processing apparatuses, and a fixed contact pattern of the switch device including the same. In addition, particularly, the switch device is a push switch device of a type that shorts a plurality of fixed contacts from each other by a movable contact. More specifically, the present invention relates to a fixed contact pattern and a switch device, capable of reliably shorting fixed contacts from each other even in a case where the movable contact is pushed and touched on a fixed contact in a state where the movable contact is inclined, and particularly, to a fixed contact pattern capable of being miniaturized, and a switch device including the same.
2. Description of the Related Art
Conventionally, a contact pattern having the shape shown in FIG. 12 is suggested as a contact pattern provided on a printed circuit board of a key switch (see, for example Japanese Unexamined Patent Application Publication No. 2001-210179). A contact pattern 100 that becomes the fixed contact has a substantially oblong planar shape, and with an I-shaped first gap 101 extending in the direction of a minor axis as a center, substantially V-shaped second gaps 102 are provided on both sides of the first gap, and substantially U-shaped third gaps 103 are provided on both sides of the first gap. Also, six conductive layers 104a-104f are formed so as to be filled between the gaps 101 to 103.
Among the six conductive layers 104a to 104f, for example, the conductive layers 104a, 104c, and 104e are electrically connected, and the conductive layers 104b, 104d, and 104f are electrically connected. Also, a group of the former conductive layers 104a, 104c, and 104e, and a group of the latter conductive layers 104b, 104d, and 104f are electrically insulated from each other by the gaps 101 to 103.
When, for example, a left end of a conductive movable contact (not shown) that has a substantially oblong planar shape similarly is pressed against the contact pattern 100, the conductive layer 104b and the conductive layer 104c are electrically connected via the movable contact, and both groups are shorted from each other by the movable contact, and thus, an ON signal is output from a key switch.
In addition, as this type of contact pattern, those described in Japanese Unexamined Patent Application Publication Nos. 7-50112 and 8-7690
Meanwhile, in the contact pattern 100 shown in FIG. 12, when a distance θ3 from one open end of the first gap 101 to one open end of the second gap 102 and a distance θ4 from one open end of the second gap 102 to the other open end thereof are compared with each other, the distance θ4 is quite longer than the distance θ3 (θ3<<θ4). If there are no conductive layer 104c which are not electrically connected the conductive layer 104b and no gap 103, in the course of this distance θ4, even if the left end of the conductive movable contact is pressed as mentioned above, this cannot be detected, which becomes a non-sensitive region.
In order to avoid this, it is necessary to provide the inverted U-shaped third gap 103, and the conductive layer 104c surrounded by the gap, near the left end of the contact pattern 100. This is also the same near a right end of the contact pattern 100. Ultimately, the whole contact pattern 100 needs five gaps 101 to 103 and six conductive layers 104a to 104f in total. As a result, there is a drawback that the pattern become complicated, and large-sized.